diff --git a/README.md b/README.md
index c9e6c3bb13..169399aac8 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,10 @@
+# Automatic memory management
+
+This version can be run stand alone, but it's more meant as proof of concept so other forks can implement similar changes.
+
+Allows to use resolutions that require up to 64x more VRAM than possible on the default CompVis build
+
+
 # Stable Diffusion
 *Stable Diffusion was made possible thanks to a collaboration with [Stability AI](https://stability.ai/) and [Runway](https://runwayml.com/) and builds upon our previous work:*
 
diff --git a/ldm/modules/attention.py b/ldm/modules/attention.py
index f4eff39ccb..a0f4f18b80 100644
--- a/ldm/modules/attention.py
+++ b/ldm/modules/attention.py
@@ -1,3 +1,4 @@
+import gc
 from inspect import isfunction
 import math
 import torch
@@ -89,7 +90,7 @@ def forward(self, x):
         b, c, h, w = x.shape
         qkv = self.to_qkv(x)
         q, k, v = rearrange(qkv, 'b (qkv heads c) h w -> qkv b heads c (h w)', heads = self.heads, qkv=3)
-        k = k.softmax(dim=-1)  
+        k = k.softmax(dim=-1)
         context = torch.einsum('bhdn,bhen->bhde', k, v)
         out = torch.einsum('bhde,bhdn->bhen', context, q)
         out = rearrange(out, 'b heads c (h w) -> b (heads c) h w', heads=self.heads, h=h, w=w)
@@ -161,7 +162,6 @@ def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0.
         self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
         self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
         self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
-
         self.to_out = nn.Sequential(
             nn.Linear(inner_dim, query_dim),
             nn.Dropout(dropout)
@@ -170,27 +170,58 @@ def __init__(self, query_dim, context_dim=None, heads=8, dim_head=64, dropout=0.
     def forward(self, x, context=None, mask=None):
         h = self.heads
 
-        q = self.to_q(x)
+        q_in = self.to_q(x)
         context = default(context, x)
-        k = self.to_k(context)
-        v = self.to_v(context)
+        k_in = self.to_k(context)
+        v_in = self.to_v(context)
+        del context, x
 
-        q, k, v = map(lambda t: rearrange(t, 'b n (h d) -> (b h) n d', h=h), (q, k, v))
+        q, k, v = map(lambda t: rearrange(t, 'b n (h d) -> (b h) n d', h=h), (q_in, k_in, v_in))
+        del q_in, k_in, v_in
 
-        sim = einsum('b i d, b j d -> b i j', q, k) * self.scale
+        r1 = torch.zeros(q.shape[0], q.shape[1], v.shape[2], device=q.device)
 
-        if exists(mask):
-            mask = rearrange(mask, 'b ... -> b (...)')
-            max_neg_value = -torch.finfo(sim.dtype).max
-            mask = repeat(mask, 'b j -> (b h) () j', h=h)
-            sim.masked_fill_(~mask, max_neg_value)
+        stats = torch.cuda.memory_stats(q.device)
+        mem_active = stats['active_bytes.all.current']
+        mem_reserved = stats['reserved_bytes.all.current']
+        mem_free_cuda, _ = torch.cuda.mem_get_info(torch.cuda.current_device())
+        mem_free_torch = mem_reserved - mem_active
+        mem_free_total = mem_free_cuda + mem_free_torch
 
-        # attention, what we cannot get enough of
-        attn = sim.softmax(dim=-1)
+        gb = 1024 ** 3
+        tensor_size = q.shape[0] * q.shape[1] * k.shape[1] * q.element_size()
+        modifier = 3 if q.element_size() == 2 else 2.5
+        mem_required = tensor_size * modifier
+        steps = 1
 
-        out = einsum('b i j, b j d -> b i d', attn, v)
-        out = rearrange(out, '(b h) n d -> b n (h d)', h=h)
-        return self.to_out(out)
+
+        if mem_required > mem_free_total:
+            steps = 2**(math.ceil(math.log(mem_required / mem_free_total, 2)))
+            # print(f"Expected tensor size:{tensor_size/gb:0.1f}GB, cuda free:{mem_free_cuda/gb:0.1f}GB "
+            #      f"torch free:{mem_free_torch/gb:0.1f} total:{mem_free_total/gb:0.1f} steps:{steps}")
+
+        if steps > 64:
+            max_res = math.floor(math.sqrt(math.sqrt(mem_free_total / 2.5)) / 8) * 64
+            raise RuntimeError(f'Not enough memory, use lower resolution (max approx. {max_res}x{max_res}). '
+                               f'Need: {mem_required/64/gb:0.1f}GB free, Have:{mem_free_total/gb:0.1f}GB free')
+
+        slice_size = q.shape[1] // steps if (q.shape[1] % steps) == 0 else q.shape[1]
+        for i in range(0, q.shape[1], slice_size):
+            end = i + slice_size
+            s1 = einsum('b i d, b j d -> b i j', q[:, i:end], k) * self.scale
+
+            s2 = s1.softmax(dim=-1, dtype=q.dtype)
+            del s1
+
+            r1[:, i:end] = einsum('b i j, b j d -> b i d', s2, v)
+            del s2
+
+        del q, k, v
+
+        r2 = rearrange(r1, '(b h) n d -> b n (h d)', h=h)
+        del r1
+
+        return self.to_out(r2)
 
 
 class BasicTransformerBlock(nn.Module):
diff --git a/ldm/modules/diffusionmodules/model.py b/ldm/modules/diffusionmodules/model.py
index 533e589a20..de3ce38c6e 100644
--- a/ldm/modules/diffusionmodules/model.py
+++ b/ldm/modules/diffusionmodules/model.py
@@ -1,4 +1,5 @@
 # pytorch_diffusion + derived encoder decoder
+import gc
 import math
 import torch
 import torch.nn as nn
@@ -32,7 +33,11 @@ def get_timestep_embedding(timesteps, embedding_dim):
 
 def nonlinearity(x):
     # swish
-    return x*torch.sigmoid(x)
+    t = torch.sigmoid(x)
+    x *= t
+    del t
+
+    return x
 
 
 def Normalize(in_channels, num_groups=32):
@@ -119,18 +124,30 @@ def __init__(self, *, in_channels, out_channels=None, conv_shortcut=False,
                                                     padding=0)
 
     def forward(self, x, temb):
-        h = x
-        h = self.norm1(h)
-        h = nonlinearity(h)
-        h = self.conv1(h)
+        h1 = x
+        h2 = self.norm1(h1)
+        del h1
+
+        h3 = nonlinearity(h2)
+        del h2
+
+        h4 = self.conv1(h3)
+        del h3
 
         if temb is not None:
-            h = h + self.temb_proj(nonlinearity(temb))[:,:,None,None]
+            h4 = h4 + self.temb_proj(nonlinearity(temb))[:,:,None,None]
 
-        h = self.norm2(h)
-        h = nonlinearity(h)
-        h = self.dropout(h)
-        h = self.conv2(h)
+        h5 = self.norm2(h4)
+        del h4
+
+        h6 = nonlinearity(h5)
+        del h5
+
+        h7 = self.dropout(h6)
+        del h6
+
+        h8 = self.conv2(h7)
+        del h7
 
         if self.in_channels != self.out_channels:
             if self.use_conv_shortcut:
@@ -138,7 +155,7 @@ def forward(self, x, temb):
             else:
                 x = self.nin_shortcut(x)
 
-        return x+h
+        return x + h8
 
 
 class LinAttnBlock(LinearAttention):
@@ -174,32 +191,68 @@ def __init__(self, in_channels):
                                         stride=1,
                                         padding=0)
 
-
     def forward(self, x):
         h_ = x
         h_ = self.norm(h_)
-        q = self.q(h_)
-        k = self.k(h_)
+        q1 = self.q(h_)
+        k1 = self.k(h_)
         v = self.v(h_)
 
         # compute attention
-        b,c,h,w = q.shape
-        q = q.reshape(b,c,h*w)
-        q = q.permute(0,2,1)   # b,hw,c
-        k = k.reshape(b,c,h*w) # b,c,hw
-        w_ = torch.bmm(q,k)     # b,hw,hw    w[b,i,j]=sum_c q[b,i,c]k[b,c,j]
-        w_ = w_ * (int(c)**(-0.5))
-        w_ = torch.nn.functional.softmax(w_, dim=2)
+        b, c, h, w = q1.shape
+
+        q2 = q1.reshape(b, c, h*w)
+        del q1
+
+        q = q2.permute(0, 2, 1)   # b,hw,c
+        del q2
+
+        k = k1.reshape(b, c, h*w) # b,c,hw
+        del k1
+
+        h_ = torch.zeros_like(k, device=q.device)
+
+        stats = torch.cuda.memory_stats(q.device)
+        mem_active = stats['active_bytes.all.current']
+        mem_reserved = stats['reserved_bytes.all.current']
+        mem_free_cuda, _ = torch.cuda.mem_get_info(torch.cuda.current_device())
+        mem_free_torch = mem_reserved - mem_active
+        mem_free_total = mem_free_cuda + mem_free_torch
+
+        tensor_size = q.shape[0] * q.shape[1] * k.shape[2] * q.element_size()
+        mem_required = tensor_size * 2.5
+        steps = 1
+
+        if mem_required > mem_free_total:
+            steps = 2**(math.ceil(math.log(mem_required / mem_free_total, 2)))
+
+        slice_size = q.shape[1] // steps if (q.shape[1] % steps) == 0 else q.shape[1]
+        for i in range(0, q.shape[1], slice_size):
+            end = i + slice_size
+
+            w1 = torch.bmm(q[:, i:end], k)     # b,hw,hw    w[b,i,j]=sum_c q[b,i,c]k[b,c,j]
+            w2 = w1 * (int(c)**(-0.5))
+            del w1
+            w3 = torch.nn.functional.softmax(w2, dim=2, dtype=q.dtype)
+            del w2
 
-        # attend to values
-        v = v.reshape(b,c,h*w)
-        w_ = w_.permute(0,2,1)   # b,hw,hw (first hw of k, second of q)
-        h_ = torch.bmm(v,w_)     # b, c,hw (hw of q) h_[b,c,j] = sum_i v[b,c,i] w_[b,i,j]
-        h_ = h_.reshape(b,c,h,w)
+            # attend to values
+            v1 = v.reshape(b, c, h*w)
+            w4 = w3.permute(0, 2, 1)   # b,hw,hw (first hw of k, second of q)
+            del w3
 
-        h_ = self.proj_out(h_)
+            h_[:, :, i:end] = torch.bmm(v1, w4)     # b, c,hw (hw of q) h_[b,c,j] = sum_i v[b,c,i] w_[b,i,j]
+            del v1, w4
 
-        return x+h_
+        h2 = h_.reshape(b, c, h, w)
+        del h_
+
+        h3 = self.proj_out(h2)
+        del h2
+
+        h3 += x
+
+        return h3
 
 
 def make_attn(in_channels, attn_type="vanilla"):
@@ -540,31 +593,54 @@ def forward(self, z):
         temb = None
 
         # z to block_in
-        h = self.conv_in(z)
+        h1 = self.conv_in(z)
 
         # middle
-        h = self.mid.block_1(h, temb)
-        h = self.mid.attn_1(h)
-        h = self.mid.block_2(h, temb)
+        h2 = self.mid.block_1(h1, temb)
+        del h1
+
+        h3 = self.mid.attn_1(h2)
+        del h2
+
+        h = self.mid.block_2(h3, temb)
+        del h3
+
+        # prepare for up sampling
+        gc.collect()
+        torch.cuda.empty_cache()
 
         # upsampling
         for i_level in reversed(range(self.num_resolutions)):
             for i_block in range(self.num_res_blocks+1):
                 h = self.up[i_level].block[i_block](h, temb)
                 if len(self.up[i_level].attn) > 0:
-                    h = self.up[i_level].attn[i_block](h)
+                    t = h
+                    h = self.up[i_level].attn[i_block](t)
+                    del t
+
             if i_level != 0:
-                h = self.up[i_level].upsample(h)
+                t = h
+                h = self.up[i_level].upsample(t)
+                del t
 
         # end
         if self.give_pre_end:
             return h
 
-        h = self.norm_out(h)
-        h = nonlinearity(h)
-        h = self.conv_out(h)
+        h1 = self.norm_out(h)
+        del h
+
+        h2 = nonlinearity(h1)
+        del h1
+
+        h = self.conv_out(h2)
+        del h2
+
         if self.tanh_out:
-            h = torch.tanh(h)
+            t = h
+            h = torch.tanh(t)
+            del t
+
         return h
 
 
diff --git a/scripts/img2img.py b/scripts/img2img.py
index 421e2151d9..04b88b54f1 100644
--- a/scripts/img2img.py
+++ b/scripts/img2img.py
@@ -196,8 +196,12 @@ def main():
     opt = parser.parse_args()
     seed_everything(opt.seed)
 
+    # needed when model is in half mode, remove if not using half mode
+    torch.set_default_tensor_type(torch.HalfTensor)
+    
     config = OmegaConf.load(f"{opt.config}")
     model = load_model_from_config(config, f"{opt.ckpt}")
+    model = model.half()
 
     device = torch.device("cuda") if torch.cuda.is_available() else torch.device("cpu")
     model = model.to(device)
diff --git a/scripts/txt2img.py b/scripts/txt2img.py
index 59c16a1db8..a08f522988 100644
--- a/scripts/txt2img.py
+++ b/scripts/txt2img.py
@@ -236,8 +236,12 @@ def main():
 
     seed_everything(opt.seed)
 
+    # needed when model is in half mode, remove if not using half mode
+    torch.set_default_tensor_type(torch.HalfTensor)
+
     config = OmegaConf.load(f"{opt.config}")
     model = load_model_from_config(config, f"{opt.ckpt}")
+    model = model.half()
 
     device = torch.device("cuda") if torch.cuda.is_available() else torch.device("cpu")
     model = model.to(device)